What unusual ingredients have you used to make pasta sauce?

I wanted something other than a tomato-based or cream-based sauce for pasta the other day, so I stood there staring into the open refrigerator. I pulled out a baked yellow sweet potato, red miso and butter. While about 2 T butter and about 1/4 C water warmed in the micro, I mashed the sweet potato well with a fork. After dissolving about 1 T red miso in the hot butter-water, I stirred in the mashed sweet potato. (Results should be creamy; if too thick, add more water.)

The result had a distinct miso flavor from my tasting spoon, but when mixed with cooked pasta and some leftover veges, the whole thing seemed to come together nicely. I'd definitely do it again.

What unusual ingredients have you used in making non-tomato-based pasta sauce?

If you're straying away from Italianish pasta sauces and into Japaneseish pasta sauces they do all kinds of crazy sauces here. In my head I tend to differentiate them from "pasta" and consider them very different from Italian pasta and their own separate entity.

There is a lot of pork belly used here in pasta, with ponzu sauce or with soy sauce. There is sea urchin or cod roe usually in a cream based sauce though.

Last winter I made stuffed shells but made the sauce from butternut squash instead of tomato. I think thy were filled with cheese or cheese and spinach. I used some warm spices in the sauce like cinnamOn and nutmeg as well. It really turned out well.